Key Word Definitions
Term Definition
A push or pull that can change the motion or shape of an
Force
object.
A force that occurs when two objects are physically
Direct (Contact)
touching.
A force that acts at a distance without physical contact, like
Indirect (Non-contact)
gravity or magnetism.
The overall force acting on an object after all the individual
Net force
forces are combined.
Newton The unit used to measure force (symbol: N).
A tool used to measure force or weight using a spring
Spring Balance
mechanism.
The force between charged objects, where opposite
Electrostatic Force
charges attract and like charges repel.
Gravitational Force The attractive force between two objects due to their mass.
The amount of matter in an object; measured in kilograms
Mass
(kg).
The force of gravity acting on an object’s mass; measured in
Weight
newtons (N).
The ends of a magnet where the magnetic force is
Magnetic poles
strongest—north and south poles.
A magnet created by electricity, usually involving a wire coil
Electromagnet
around a metal core.
A rigid bar that rotates around a fixed point (fulcrum) to lift
Lever (Simple Machine)
or move loads with less effort.
Inclined Plane (Simple A flat surface set at an angle to help lift objects with less
Machine) force.
A force that resists motion when two surfaces move or try
Friction
to move across each other.
, Balanced / Unbalanced Forces
Balanced Forces
• Occur when all forces acting on an object cancel each other out.
• The net force is zero (0 N).
• There is no change in motion:
o If the object is at rest, it stays at rest.
o If the object is moving, it continues moving at a constant speed in the
same direction.
• Example: A book resting on a table – gravity pulls it down, the table pushes it up
with equal force.
Unbalanced Forces
• Happen when one force is stronger than the opposing force(s).
• The net force is not zero.
• Motion changes:
o The object may start moving, stop, speed up, slow down, or change
direction.
• Example: Kicking a soccer ball – your foot applies an unbalanced force that
moves the ball.
Key PointS
• Balanced forces = no motion change
• Unbalanced forces = motion changes (acceleration)
Balanced / Unbalanced Forces Questions
Multiple Choice
1. What happens when forces acting on an object are balanced?
A. The object speeds up
B. The object changes direction
C. The object stays still or moves at a constant speed
D. The object slows down
Term Definition
A push or pull that can change the motion or shape of an
Force
object.
A force that occurs when two objects are physically
Direct (Contact)
touching.
A force that acts at a distance without physical contact, like
Indirect (Non-contact)
gravity or magnetism.
The overall force acting on an object after all the individual
Net force
forces are combined.
Newton The unit used to measure force (symbol: N).
A tool used to measure force or weight using a spring
Spring Balance
mechanism.
The force between charged objects, where opposite
Electrostatic Force
charges attract and like charges repel.
Gravitational Force The attractive force between two objects due to their mass.
The amount of matter in an object; measured in kilograms
Mass
(kg).
The force of gravity acting on an object’s mass; measured in
Weight
newtons (N).
The ends of a magnet where the magnetic force is
Magnetic poles
strongest—north and south poles.
A magnet created by electricity, usually involving a wire coil
Electromagnet
around a metal core.
A rigid bar that rotates around a fixed point (fulcrum) to lift
Lever (Simple Machine)
or move loads with less effort.
Inclined Plane (Simple A flat surface set at an angle to help lift objects with less
Machine) force.
A force that resists motion when two surfaces move or try
Friction
to move across each other.
, Balanced / Unbalanced Forces
Balanced Forces
• Occur when all forces acting on an object cancel each other out.
• The net force is zero (0 N).
• There is no change in motion:
o If the object is at rest, it stays at rest.
o If the object is moving, it continues moving at a constant speed in the
same direction.
• Example: A book resting on a table – gravity pulls it down, the table pushes it up
with equal force.
Unbalanced Forces
• Happen when one force is stronger than the opposing force(s).
• The net force is not zero.
• Motion changes:
o The object may start moving, stop, speed up, slow down, or change
direction.
• Example: Kicking a soccer ball – your foot applies an unbalanced force that
moves the ball.
Key PointS
• Balanced forces = no motion change
• Unbalanced forces = motion changes (acceleration)
Balanced / Unbalanced Forces Questions
Multiple Choice
1. What happens when forces acting on an object are balanced?
A. The object speeds up
B. The object changes direction
C. The object stays still or moves at a constant speed
D. The object slows down
